The present invention relates to subcutaneous access and more particularly hemodialysis apparatus of the general type disclosed in copending U.S. patent applications of Frank Prosl, Ser. No. 08/485,498, filed Jun. 7, 1995 and Ser. No. 08/631,801, filed Apr. 11, 1996. The disclosures of said applications are incorporated herein by reference as though set out at length herein. The copending applications disclose and claim apparatus for assuring high flow rates for enhancing hemodialysis. Such apparatus includes a connected pair of catheter end attaching and cannula end locking devices (or a single such device or separate unconnected such devices) that is subcutaneously implanted. Each such device is arranged with an internal passage, one end of which can have a catheter proximal end attached thereto (the distal ends of the catheters of the two devices being at optimal regions of the patient for suction [e.g., atrium] and return [e.g., jugular vein] of blood). Each device or a connected pair of such devices is subcutaneously implanted and the other end of the internal passage of each device is just under the skin and easily accessed. A cannula (e.g. a hollow needle) or other conduit is locked into each device and used for blood flow between the device and external to the patient pumping/dialysis apparatus or other blood processing.
The present invention is also useful for other liquid transfer purposes in and out of human and animal bodies including transfer of externally prepared solutions for cleaning, flushing, dialysis, chemical agent delivery, transfusions, blood donation, insufflation, wound drainage, etc.
It is a principal object of the invention to optimize fluid flow in hemodialysis particularly and in other applications referred to generally, above.
It is a further object of the invention to enhance the devices to more effectively lock in a cannula to the device to avoid inadvertent separation, yet allow ease of deliberate release of the cannula.
It is a further object to the invention to minimize internal fluid collection zones in such a device.
It is a further object of the invention to provide ease of manufacture and assembly of such device consistent with enhanced locking.
It is a further object of the invention to minimize irritation and other adverse effects associated with intermittent skin puncture over a course of days, months or years of repetitive access.
A further object of the invention is to establish economy of the lock devices for disposability.
It is a further object of the invention to provide enhanced cannula and obturator handling external to a patient via hub devices coordinated with the structure and functions of the locking devices.
It is also an object of the invention to accommodate multiples of the foregoing objects together.